The present invention relates to PTO driven implements and more specifically relates to drivelines for such implements.
Implements driven from the power-take-off (PTO) of a towing tractor have drivelines which usually include a telescopic shaft coupled between the tractor PTO and a pedestal shaft supported by the implement draft tongue. These arrangements have a problem with the telescopic shaft either bottoming out or coming apart during certain conditions. Specifically, the telescopic shaft can bottom out when the tractor pitches up and/or rolls toward the implement when the tractor is turning and can separate when the tractor pitches down and/or rolls away from the implement when the tractor is travelling more or less straight ahead.
Heretofore, there have been two solutions to this problem. One solution has been to provide draw bar extensions on the tractor to provide more length for the telescopic drive shaft. This extra length allows the tractor to move through a greater range before the drive shaft either bottoms out or separates. This solution is disclosed in U.S. Pat. No. 3,557,892 issued on 26 Jan. 1971. Another solution has been to allow the pedestal shaft to pivot out of the way when the telescopic shaft bottoms out. This approach is disclosed in U.S. Pat. No. 3,908,398 issued on 30 Sep. 1975 and U.S. Pat. No. 4,020,913 issued on 3 May 1977.
The first solution mentioned above has the drawbacks of requiring parts to be stored when not in use and of being cumbersome to install and remove, while the latter mentioned solution has the drawbacks of requiring a relatively large number of parts to be assembled resulting in the assembly being relatively cumbersome and expensive.